[This puzzle comes from the 2022 US Sudoku Grand Prix round. This next set of variations uses a shared double eights theme, in this case with both two large eight shapes and at least two given eights. I tried hard to find a unique Thermo-Sudoku pattern that didn’t need the extra non-eight digit in the center cell, but couldn’t get one with a smooth look for the other thermometers. I still liked how the final puzzle got to a moderate difficulty puzzle appropriate for a competition.]

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Theme: Double Eights

Author/Opus: This is the 439th puzzle from Thomas Snyder, aka Dr. Sudoku.

Rules: Standard Thermo-Sudoku rules.

Estimated Difficulty: 3 stars

Solution: PDF

Note: Follow this link for more Thermo-Sudoku puzzles. If you are new to this puzzle type, here are our easiest Thermo-Sudoku to get started on. More Thermo-Sudoku puzzles can be found in The Art of Sudoku 2 and Masterpiece Sudoku Mix 2.

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Theme: Sudoku Crew

Author/Opus: This is the 4th puzzle from guest contributor Michael Rios.

Rules: Standard Killer Sudoku rules and Thermo-Sudoku rules. Specifically, insert a number from 1 to 9 into each cell so that no number repeats in any row, column, or bold region. Also, the sum of the numbers in each cage must equal the value given in the upper-left corner of that cage. Numbers cannot repeat inside a cage. Some thermometer shapes are in the grid; numbers must be strictly increasing from the round bulb to the flat end.

Difficulty: 4 stars

Time Standards (highlight to view): Grandmaster = 7:30, Master = 11:15, Expert = 22:30

Solution: PDF and solving video.

Note: Follow this link for more Killer Sudoku and this link for classic Sudoku. More Killer Sudoku puzzles can be found in Killer Sudoku by Serkan Yürekli. Follow this link for more Thermo-Sudoku puzzles. If you are new to this puzzle type, here are our easiest Thermo-Sudoku to get started on. More Thermo-Sudoku puzzles can be found in The Art of Sudoku 2 and Masterpiece Sudoku Mix 2.

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Theme: Lion Face

Author/Opus: This is the 17th puzzle from guest contributor Rajesh Kumar.

Rules: Standard Thermo-Sudoku rules.

Difficulty: 2.5 stars

Time Standards (highlight to view): Grandmaster = 2:45, Master = 5:00, Expert = 10:00

Solution: PDF and solving video.

Note: Follow this link for more Thermo-Sudoku puzzles. If you are new to this puzzle type, here are our easiest Thermo-Sudoku to get started on. More Thermo-Sudoku puzzles can be found in The Art of Sudoku 2 and Masterpiece Sudoku Mix 2.

Since 2021, we have posted some extra difficult Sunday Stumpers, about once a month. These will be quite tough puzzles, but with a logical path to be found (and solution videos to help). This fifth Sunday Stumper of 2022 is a combination of Arrow Sudoku and Thermo-Sudoku by Jonas Gleim.

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Theme: Compass

Author/Opus: This is the 12th puzzle from guest contributor Jonas Gleim.

Rules: Standard Arrow Sudoku and Thermo-Sudoku rules.

Difficulty: 5 stars

Time Standards (highlight to view): Grandmaster = 18:00, Master = 25:00, Expert = 50:00

Solution: PDF and solving video.

Note: Follow this link for other classic Sudoku. If you are new to this puzzle type, here are our easiest Sudoku to get started on. More classic Sudoku puzzles can be found in The Art of Sudoku, The Art of Sudoku 2 and in our beginner-friendly collection Intro to GMPuzzles by Serkan Yürekli.

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Theme: 3/25

Author/Opus: This is the 409th puzzle from Thomas Snyder, aka Dr. Sudoku.

Rules: Standard Thermo-Sudoku rules.

Difficulty: 4.5 stars

Time Standards (highlight to view): Grandmaster = 10:00, Master = 17:30, Expert = 35:00

Solution: PDF; a solution video from the Cracking the Cryptic team is available here. Thomas may come back to write a “how this was made” type video in the coming weeks but the CtC solve captures most of the intended logic.

Note: Follow this link for more Thermo-Sudoku puzzles. If you are new to this puzzle type, here are our easiest Thermo-Sudoku to get started on. More Thermo-Sudoku puzzles can be found in The Art of Sudoku 2 and Masterpiece Sudoku Mix 2.

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Theme: Dumbbell

Author/Opus: This is the 6th puzzle from guest contributor Kishore Kumar Sridharan.

Rules: Standard Thermo-Sudoku rules.

Difficulty: 4 stars

Time Standards (highlight to view): Grandmaster = 6:45, Master = 10:30, Expert = 21:00

Solution: PDF; a solution video is also available here.

Note: Follow this link for more Thermo-Sudoku puzzles. If you are new to this puzzle type, here are our easiest Thermo-Sudoku to get started on. More Thermo-Sudoku puzzles can be found in The Art of Sudoku 2 and Masterpiece Sudoku Mix 2.

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Theme: Warm Up for 2022

Author/Opus: This is the 5th puzzle from guest contributor R. Kumaresan.

Rules: Standard Thermo-Sudoku rules.

Difficulty: 3.5 stars

Time Standards (highlight to view): Grandmaster = 5:15, Master = 7:15, Expert = 14:30

Solution: PDF; a solution video is also available here.

Note: Follow this link for more Thermo-Sudoku puzzles. If you are new to this puzzle type, here are our easiest Thermo-Sudoku to get started on. More Thermo-Sudoku puzzles can be found in The Art of Sudoku 2 and Masterpiece Sudoku Mix 2.

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Theme: Christmas Tree

Author/Opus: This is the 397th puzzle from Thomas Snyder, aka Dr. Sudoku.

Rules: Standard Thermo-Sudoku rules.

Difficulty: 4.5 stars

Time Standards (highlight to view): Grandmaster = 7:30, Master = 16:30, Expert = 33:00

Solution: PDF; a solution video is also available here.

Note: Follow this link for more Thermo-Sudoku puzzles. If you are new to this puzzle type, here are our easiest Thermo-Sudoku to get started on. More Thermo-Sudoku puzzles can be found in The Art of Sudoku 2 and Masterpiece Sudoku Mix 2.

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Theme: 20-20 Vision

Author/Opus: This is the 1st puzzle from guest contributor Teddy Tan.

Rules: Standard Thermo-Sudoku rules.

Difficulty: 3.5 stars

Time Standards (highlight to view): Grandmaster = 5:00, Master = 7:30, Expert = 15:00

Solution: PDF; a solution video is also available here.

Note: Follow this link for more Thermo-Sudoku puzzles. If you are new to this puzzle type, here are our easiest Thermo-Sudoku to get started on. More Thermo-Sudoku puzzles can be found in The Art of Sudoku 2 and Masterpiece Sudoku Mix 2.

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Theme: Square Knots

Author/Opus: This is the 2nd puzzle from guest contributor Michael Rios.

Rules: Standard Sudoku rules. Also, some arrow shapes are in the grid; the sum of the numbers along the path of each arrow must equal the number in the circled cell (numbers can repeat on an arrow). Some cages are in the grid marked by dashed lines; the sum of the numbers in these cages must equal the value given in the upper-left corner of that cage (numbers cannot repeat inside a cage). Some dots are given between two cells; a white dot shows that the numbers in those cells are consecutive and a black dot shows that the number in one of the cells has twice the value of the other (adjacent cells without dots may or may not follow these rules). Finally, some thermometer shapes are in the grid; the numbers along the thermometer must be strictly increasing from the round bulb to the flat end.

Difficulty: 4.5 stars

Time Standards (highlight to view): Grandmaster = 10:45, Master = 18:45, Expert = 37:30

Solution: PDF; a solution video is also available here.

Note: Follow this link for more Arrow Sudoku. Follow this link for more Thermo-Sudoku puzzles. More Arrow and Thermo-Sudoku puzzles can be found in The Art of Sudoku 2. More Killer Sudoku puzzles can be found in Killer Sudoku by Serkan Yürekli.